The present invention relates to separation of fluid mixtures of different densities, and particularly the present invention relates to a liquid and gas separator adapted to be incorporated in the production tubing of a liquid well. In liquid-producing wells and particularly in deep producing wells where liquid is pumped to the surface, a problem is often encountered handling the gas commonly associated with the liquid in the producing formation. There is usually a substantial decrease in pressure on the liquid-gas mixture as it moves out of the liquid-bearing formation into the production well. Hydrocarbon gas, either in solution with the liquid or in the free state, expands as the gas-liquid mixture enters the production borehole. If the gas is pumped with the liquid to the surface serious difficulty is likely to be encountered with the pumping apparatus. A positive displacement pump will act as a compressor of the gas and will lose much of its efficiency in lifting liquid to the surface. In severe cases, the pump may become "gas locked" as a result pumping gas and damage to the pump may result.
Gas and liquid separators have been utilized in order to remedy this problem. Generally, the gas and liquid separator is a device which, by utilizing the different properties of the two substances, affects the separation of the liquid which is usually a mixture of oil and water and the gas and allows them to be moved to the surface through different conduits. It is in this general area that the present invention finds its utility. It should be noted, however, that the apparatus herein described is useful not only to separate well liquids and gas, but may also be used in separating any two fluid substances which have different specific gravities. An example of situations other than gas and well liquid separators where the apparatus may be used effectively include separating a gas and water mixture. Therefore, the apparatus, although described herein as primarily useful as a gas and well fluids separator, may be used to perform similar operations with no substantial alteration of the apparatus itself.
A device for separating liquid and gas is shown in U.S. Pat. No. 2,652,130, issued Sept. 15, 1953 to Cedric K. Ferguson. The device of the patent uses centrifugal force to assist in separating the gas from the liquid and provides an arrangement of conduits for transmitting the gas and liquid to the surface. There is still need, however, for a gas-liquid separator which utilizes centrifugal force in assisting the separation of the liquid and gas and provides a more direct and easy passage of the liquid and gas to the surface thus resulting in less pressure drop in the separator and also simpler construction.